As a device that relays electrical energy in the form of mechanical energy, a motor is used in many different forms in various machines, electric products, and electronic products. Because existing motors rotate about one axis and are restricted by that axis to rotating in only two directions, the motors are restricted in movement. Therefore, due to limits in how motors of the related art may be controlled in terms of rotating direction, applications of the motors were limited.
In order to solve this problem and realize greater freedom of movement for a motor, although a method of connecting multiple motors with one joint has been proposed, there is the drawback of requiring many links and a complicated converting device. To compensate for this drawback, a spherical motor having a 3-directional degree of freedom has been introduced, which is exemplified by the spherical motor disclosed in Korean registered patent 0954772 (registration date: Apr. 29, 2010). The spherical wheel motor having a freedom of rotational direction as disclosed in the above patent may be used for steering movement in automobiles and motorboats, for eye movement and arm, neck, and hip joint movement in robots.
Spherical wheel motors that can replace the wheels of transportation means such as automobiles needs to be capable of rotational movement without an axis, and require accurate positional control of the rotor and a simple structure. However, the rotors of related art spherical wheel motors are formed on the basis of a shaft, are structurally complicated due to the use of a plurality of permanent magnets, and are also limited in terms of freedom of rotation.